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The J1772 specification that every U.S.-market electric car uses allows for charging at up to 80 amps at 240 volts, provided of course that the onboard charger and car is capable of receiving that much power. Moreover, that's 80 amps at 240 volts single phase, or 19.2 kilowatts, making it easier to install than the European three-phase system. But while the specification allows for 19.2-kilowatt charging, no cars on the market today support that high a recharging rate.

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Now take a look in the "Charging Model S" subforum and read all the rants about running heavy gauge wire, upgrading to 200A or even 400A panels, blowing 100A fuses in HPWC, melting adapters and such. Could it be that currents in excess of 40A are a challenge to handle?

And why is 3phase harder to install? Just add 1 wire and triple your power.

The 30A public L2 station often is deemed "useless" for any EV with a large battery. I agree, since it will deliver a mere 6kW when running off a 208V wye leg. Now imagine a conversion to 3 phase. Boom, 10.8kW. And 3 phase AC power is available where 208V comes from.
I am well aware that this is unlikely to happen in U.S, since all EVs would require another charging port, 3 phase capable on board chargers, and residential 3 phase is something utilities just won't do in the moment. But one can dream, right?

The 30A public L2 station often is deemed "useless" for any EV with a large battery. I agree, since it will deliver a mere 6kW when running off a 208V wye leg. Now imagine a conversion to 3 phase. Boom, 10.8kW. And 3 phase AC power is available where 208V comes from.

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In some older U.S. distribution grids, residential customers get only one leg of the 208V wye. Unfortunately, this is what I have here in central Boston, so I'm capped at 8kW charging (at 40A).

I've been driving Teslas for over 3 years (as many on this forum have), and both of my cars had 70amp or greater onboard charging. Here's my observations after lots of long distance travel. These observations apply to powerful/large capacity cars like the Tesla only--I realize that a low capacity Leaf is a whole different ballgame:
- 30amp at hotels is way better than nothing and almost gets a full charge overnight, but is pretty much useless for anything but overnight or a long day somewhere like Disneyland (not that they have anything yet).
- Obviously super (or fast if compatible) is way best for long distance freeway driving. I'm not questioning whether we should have these. We absolutely want these everywhere possible. But given their expense I don't believe we're going to have full coverage from super chargers for a long time. And even when we have full freeway coverage, they still aren't always going to be where you want them to be.
- Where there isn't super/fast charging, 70-80amp charging is still incredibly helpful and actually makes long distance reasonable. It requires plenty more patience that ICE driving or using superchargers, but it's perfectly doable. Lots of us have done the 101 corridor from SF to San Diego using 70amp stations, whereas if you had to use just 30amps you'd need another day to make the trip.

My main point is given that 80amp stations usually (not always, but usually) cost little to nothing more than 30amp stations to buy and install, it's silly for any location to install a 30amp station instead of an 80amp unless there's some local issue (available line power at the location for example).

Now take a look in the "Charging Model S" subforum and read all the rants about running heavy gauge wire, upgrading to 200A or even 400A panels, blowing 100A fuses in HPWC, melting adapters and such. Could it be that currents in excess of 40A are a challenge to handle?

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A 125A 3 phase panel costs about the same as a single 200A panel (both ~$100), so that part is a wash. As for wiring, if you can keep the other wires and just add another one you can probably save some money with 3-phase. If not, it's probably a wash (10/4 wiring vs 8/3 or 6/3 wiring).

As for the problems with the Model S HPWC and adapters, I think that may have more to do with higher volume scaling than anything (which had brought prices down). The Roadster HPWC did not have the same issues even though it went up to 70A.

A lot of the places here do not have 3-phase service anyways, so it's kind of N/A in most cases.

On topic: I think why most places have 30A is because there really weren't much higher power options (although this is mainly from automakers and charger manufacturers saying there is no need for higher power versions). Only Clipper Creek made the higher power 70A versions (now Eaton and Siemens has joined the game).

Remember, too, that "getting to full" isn't always the relevant metric. Example: from Boston to the summer home of the Boston Symphony in Tanglewood is 130 miles, mostly on I-90. The 260-mile RT is possible but leaves very little cushion. If Tanglewood had even 30A L2 charging, I could add ~80 miles during the course of a concert, providing ample charge to get home.

Is there an issue with the maximum current from the grid if multiple cars were charging simultaneously, e.g. at Tanglewood? I don't know how power companies charge for connections, but 10 cars at 30 amps vs 10 cars at 70 amps sounds like the grid connection might get expensive.

It still appears to me that while level 2 chargers are the right answer for overnight or multiple hour stops, for highway driving, high power DC is really essential for widespread EV acceptance. I'm sure there are people who don't mind doubling their journey time compared to an ICE, but I'm very doubtful that most people will accept it.

I've been driving Teslas for over 3 years (as many on this forum have), and both of my cars had 70amp or greater onboard charging. Here's my observations after lots of long distance travel. These observations apply to powerful/large capacity cars like the Tesla only--I realize that a low capacity Leaf is a whole different ballgame:
- 30amp at hotels is way better than nothing and almost gets a full charge overnight, but is pretty much useless for anything but overnight or a long day somewhere like Disneyland (not that they have anything yet).
- Obviously super (or fast if compatible) is way best for long distance freeway driving. I'm not questioning whether we should have these. We absolutely want these everywhere possible. But given their expense I don't believe we're going to have full coverage from super chargers for a long time. And even when we have full freeway coverage, they still aren't always going to be where you want them to be.
- Where there isn't super/fast charging, 70-80amp charging is still incredibly helpful and actually makes long distance reasonable. It requires plenty more patience that ICE driving or using superchargers, but it's perfectly doable. Lots of us have done the 101 corridor from SF to San Diego using 70amp stations, whereas if you had to use just 30amps you'd need another day to make the trip.

My main point is given that 80amp stations usually (not always, but usually) cost little to nothing more than 30amp stations to buy and install, it's silly for any location to install a 30amp station instead of an 80amp unless there's some local issue (available line power at the location for example).

Is there an issue with the maximum current from the grid if multiple cars were charging simultaneously, e.g. at Tanglewood? I don't know how power companies charge for connections, but 10 cars at 30 amps vs 10 cars at 70 amps sounds like the grid connection might get expensive.

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Maybe if there are a bunch of these at a lower power location. But in reality I see chargers at two kinds of places i'd stop on road trips:
- Small businesses like restaurants (or places like the Rabobanks next to restaurants) with just one station. This is fine. Any recently built house or business can add a 70amp station without issue i believe. (Maybe someone can fact check this for me, but my 1976 house only needed a panel upgrade)
- A mall will have more stations, but i believe these locations are already equipped for plenty of power capacity to support their tenants.

My guess is its not a power capacity issue. But again, I'm making an educated guess based on observation and deduction, not hard facts.

It still appears to me that while level 2 chargers are the right answer for overnight or multiple hour stops, for highway driving, high power DC is really essential for widespread EV acceptance. I'm sure there are people who don't mind doubling their journey time compared to an ICE, but I'm very doubtful that most people will accept it.

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Fits the zero compromise argument. I still think for a lot of people knowing that on that couple times a year that you maybe drive out of range, even if there is no supercharger, you can still add 40-60 miles / charging hour helps since it will be a long time before you can count on a Supercharger along your route wherever it may be.

It's not whether we want Superchargers. It's if a business is putting in J1772 anyway, shouldn't they at least try and put in an 80amp instead of 30 if their power can handle it given similar cost?

It's if a business is putting in J1772 anyway, shouldn't they at least try and put in an 80amp instead of 30 if their power can handle it given similar cost?

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The counter-argument is that if there is that much power available it would be better to put in two 30-amp [or 2x40-amp] rather than one 80-amp. Even as an 80A driver, you may be better off with that, given the chance of the single high-capacity outlet being blocked by a slow-charging Volt/Leaf/single-charger Model S.

There's a crying need for a dual-headed charger that can split the available power between the two heads according to what the vehicles currently plugged in are actually taking - 40:40 if both Model S, 80:0 if only one plugged in, 15:65 if one side happens to have a Leaf plugged in etc. It would be extremely easy to do, but I haven't seen any of the EVSE manufacturers offering such a thing [I'd be very happy to be proved wrong!].

Likewise, in the future places like hotels will need to allow for a significant number of their guests wanting overnight charging - one or two charging points isn't going to be enough. Providing 10 or 20 spots with 80A charging would be very expensive, and wasteful since on average each guest probably only needs 10A or so (some smaller-capacity cars that can't use more than that overnight, and even for those with the capacity of the Model S, most will arrive less than 100% empty; some may be staying more than one night etc.). But having only 10A outlets would be unhelpful for those that do need a full charge. Again, a simple scheme of load balancing could easily be implemented in the EVSEs.

IMHO 30A is just barely adequate at hotels, especially when it's really 24A (i.e. 30A circuit). Last year I stopped at a hotel with my Roadster, where they had a "30A" J1772. The Roadster was on fumes when I arrived. Luckily I slept in and had a leisurely breakfast, because after >10 hours of charging I discovered it hadn't quite finished a StandardMode charge yet. Luckily I didn't need Range Mode.

Dual Head Schneiders just suck. Limited to 30A each @ 203vac (6kw). $3000 units designed with no vision, no joy.
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Yes, likewise Aerovironment sell dual and quad, but they appear to be just mounting hardware to install 2 (or 4) of the standalone 30A chargers onto a single post.

Clipper Creek don't offer any multi-head at all.

Clipper Creek and Aerovironment advertise a 'networking' option: almost no details are given on the websites, but these seem to be about communicating via a smart meter for monitoring and wide area load management, rather than local operation to manage the load on a single circuit. Possibly these devices have the necessary hardware and it would be just a matter of software to make them communicate to share a 100A circuit between the multiple heads.